function Person(name,age){
    this.name = name;
    this.age = age;
}
Person.prototype.sayName = function(){
    console.log("my name is",this.name);
}
Person.prototype.sayAge = function(){
    console.log("my age is",this.age);
}
var p1 = new Person("moyu",12);
var p2 = new Person("momo",23);
console.log(p1 instanceof Person);
console.log(p1);
console.log(p2 instanceof Person);
console.log(p1.sayName === p2.sayName);//内存地址一样
p1.sayName();
p2.sayAge();
